In a canned linear motor armature and a canned linear motor which have been hitherto used for stage drive in a semiconductor manufacturing apparatus or for table feeding in a machine tool, and which require reduction of a temperature rise of a linear motor main body and improvement in reliability of insulation, an armature winding is covered with a can, and a refrigerant is supplied to flow through a refrigerant passage provided between the armature winding and the can, thereby recovering heat generated from the armature winding by the refrigerant and reducing the temperature rise of a surface of the linear motor (refer to, for example, Patent Documents 1 and 2).
FIG. 1 is an entire perspective view of a general canned linear motor having a movable element in which an armature is covered with a can, which shows the entire constitution common to that in a first embodiment of the invention described later and that in a related art.
In FIG. 1, a reference numeral 100 designates a stator, designates a housing, 102 designates a can, 103 designates a can fixing bolt, 104 designates a pressing plate, 105 designates an armature winding, 106 designates a terminal base, designates a refrigerant supply port, 108 designates a refrigerant discharge port, 111 designates a connection substrate, 112 designates a winding accommodating frame, 200 designates a movable element, 201 designates a field yoke support member, 202 designates a field yoke, and 203 designates a permanent magnet.
One movable element 200 includes the field yoke 202, the plural permanent magnets 203 for field arranged adjacently on the inner surface of the field yoke 202 so that polarities are alternately different, and the field yoke support member 201, and has the -shaped section. Further, the other stator 100 is so constructed that the armature winding 105 is covered with the can 102 and inserted in a hollow space in the movable element so as to be opposed to magnet arrays of the permanent magnets 203 through a gap.
Under such the constitution, the movable element 200 is supported by a not-shown linear rolling guide or a not-shown hydrostatic bearing guide so that the movable element 200 can move in relation to the stator 100 in the direction of arrows. A refrigerant is supplied from the refrigerant supply port 107 provided in the housing 101 and discharged from the refrigerant discharge port 108.
FIG. 12 shows a canned linear motor in a related art, corresponding to a front sectional view taken along the inside of a line A-A of FIG. 1 (½ model).
In FIG. 12, a reference numeral 109 is an O-ring, 110 is a refrigerant passage, and 113 is a molding resin.
The stator 100 includes the frame-shaped metallic housing 101, the plate-shaped can 102 having the outer shape of the housing 101 in order to close airtightly both opening parts of the housing 101, the can fixing bolt 103 for fixing the can 102 to the housing 101, the pressing plate 104 which has a through-hole for the can fixing bolt 103 and presses the can 102 by an equal load, the armature winding 105 arranged in the hollow part of the housing 101, the connection substrate 111 for wiring the armature winding 105, the winding accommodating frame 112 for accommodating the armature winding 105 therein, and the O-ring 109 formed to be slightly larger than the hollow part of the housing 101. The external shape of the connection substrate 111 and the external shape of the winding accommodating frame 112 are formed respectively to be slightly smaller than the hollow part of the housing 101, the connection substrate 111 is formed of a thin plate, and the winding accommodating frame is formed of a thick plate. Further, the winding accommodating frame 112 is formed to be slightly larger than the external shape of the armature winding 105 in order to accommodate the armature winding 105 therein, and has the shape of a recess in which a bottom portion is opened.
The armature winding 105, after being accommodated in the winding accommodating frame 112, is covered tightly with the connection substrate 111, and the inside of the covered portion is molded by the molding resin 113. Further, the armature winding 105 and the connection substrate 111 are electrically connected to each other. The armature winding 105 of which surroundings are thus constructed is fixed to the housing 101 through the connection substrate 111 or the winding accommodating frame 112 by a bolt (not shown). On the edges of the front and back sides of the housing 101, circulating grooves are provided, and the O-rings 109 are arranged in the grooves. Then, the cans 102 are arranged on the front and back parts of the housing 101. The pressing plate 104 is laid on the can 102 along the edge of the housing 101 and fastened by the can fixing bolt 103, so that the can 102 is fixed to the housing 101. At this time, between the can 102 and the connection substrate 111, and between the can 102 and the winding accommodating frame 112, a fixed gap is formed respectively, and this gap becomes the refrigerant passage 110. The refrigerant is supplied from the refrigerant supply port 107 provided in the housing 101 and discharged from the refrigerant discharge port 108. The refrigerant flows in the refrigerant passage 110 to cool the armature winding 105 which generates heat due to copper loss. Further, as the refrigerant, conventionally, a fluorine-based inert refrigerant which has an extremely small electric conductivity and the insulating property (for example, hydrofluoric ether (HFE) produced by Sumitomo 3M Ltd.) has been used. In recent years, by a request of more reduction of the temperature rise, there has been used water (including pure water and ultra pure water) which is large in thermal conductivity and specific heat and extremely high in heat recovery.
FIG. 13 shows a canned linear motor in the related art, corresponding to a side sectional view taken along the inside of a line B-B of FIG. 1 (½ model).
In FIG. 13, a reference numeral 120 is a lead wire, 121 is a land, 122 is a lead wire cover, and 130 is a resin. A foil pattern (not shown) for connecting the armature winding 105 and the lead wire 120 is provided for the connection substrate 111, and the land 121 is provided at a terminus of the copper foil pattern. One end of the lead wire 120 is connected to the land 121 by solder, and the other end thereof is connected to the terminal base 106. Further, the recess portion corresponding to the upper portion of the land 121 is filled with the resin 130, and the lead wire cover 122 is arranged at the boundary between the recess portion and the refrigerant passage 110.
In the thus constructed canned linear motor, a three-phase alternating current corresponding to the electric relative position of the movable element 200 and the stator 100 is supplied to the armature winding 105, whereby a thrust is generated in the movable element 200 by an action on a magnetic field formed by the permanent magnet 203. At this time, since the armature winding 105 in which heat is generated by the copper loss is cooled by the refrigerant flowing in the refrigerant passage 110, the rise of the surface temperature of the can 102 can be suppressed. Further, since the water (including pure water and ultra pure water) which is large in thermal conductivity and specific heat and high in heat recovery can be used, the rise of the surface temperature of the can 102 can be suppressed so as to be extremely low.
Patent Document 1: Japanese Patent Application No. 2004-148203 (Specification Page 7, and FIGS. 1 to 5)
Patent Document 2: JP-A-2004-312877 (Specification Pages 4 to 5, and FIG. 2)